Method for controlling an MR apparatus

Abstract

In a method for control, input magnetic field map data is received. In this case, the input magnetic field map data for at least one magnetic field type in each case describes a magnetic field map for a state that an examination object is in at an initial location in the MR apparatus. In this case, the estimated magnetic field map data for at least one magnetic field type in each case describes at least one magnetic field map for in each case a state that the examination object is in at an alternative location that is different compared to the initial location. Control data is determined by the system control unit, using the estimated magnetic field map data or using the input magnetic field map data and the estimated magnetic field map data. The control data is suitable for controlling the MR apparatus.

The invention claimed is: 
     
       1. A method for determining control data for a magnetic resonance (MR) excitation of an examination object using an MR apparatus, the method comprising:
 receiving input magnetic field map data, wherein the input magnetic field map data for at least one magnetic field type in each case describes a magnetic field map for a state that the examination object is in at an initial location in the MR apparatus; 
 determining estimated magnetic field map data, wherein the estimated magnetic field map data for at least one magnetic field type in each case describes at least one magnetic field map for in each case a state that the examination object is in at an alternative location that is different compared to the initial location; and 
 determining control data using the estimated magnetic field map data or using the input magnetic field map data and the estimated magnetic field map data, 
 wherein the control data is suitable for the MR excitation of the examination object, and 
 wherein the determining of the estimated magnetic field map data, the determining of the control data, or the determining of the estimated magnetic field map data and the determining of the control data take place based on an application of a trained function, an interpolation function, or the trained function and the interpolation function to the input magnetic field map data. 
 
     
     
       2. The method of  claim 1 , wherein the MR excitation comprises generation of at least one radio frequency (RF) transmit pulse by a transmit coil arrangement of the MR apparatus, generation of at least one gradient pulse by a gradient coil unit of the MR apparatus, or generation of the at least one radio frequency (RF) transmit pulse by the transmit coil arrangement of the MR apparatus and generation of the at least one gradient pulse by the gradient coil unit of the MR apparatus. 
     
     
       3. The method of  claim 2 , wherein the input magnetic field map data is recorded in a preliminary MR scan with the aid of the MR apparatus, and
 wherein after the preliminary MR scan, an MR excitation of the examination object takes place in a main MR scan by the transmit coil arrangement using the control data. 
 
     
     
       4. The method of  claim 3 , wherein the control data is suitable for the MR excitation in accordance with multiple excitation configurations, and
 wherein determining the control data comprises optimizing to the effect that each of the multiple excitation configurations comprises an MR excitation that is optimized for in each case a different location range of the examination object. 
 
     
     
       5. The method of  claim 4 , wherein the initial location is determined during the preliminary MR scan,
 wherein a current location of the examination object in the MR apparatus is determined during the main MR scan, 
 wherein the current location relative to the initial location is assigned to one of the different location ranges, and 
 wherein the MR excitation of the examination object takes place in accordance with the excitation configuration of the assigned location range. 
 
     
     
       6. The method of  claim 5 , wherein the initial location, the current location, or the initial location and the current location of the examination object is determined by a navigator scan, a pilot tone scan, a camera recording, or any combination thereof. 
     
     
       7. The method of  claim 3 , wherein the initial location is determined during the preliminary MR scan,
 wherein a current location of the examination object in the MR apparatus is determined during the main MR scan, and 
 wherein at least one alternative location is determined using the current location. 
 
     
     
       8. The method of  claim 1 , wherein the at least one magnetic field type comprises a B1 field, a B0 field, or the B1 field and the B0 field. 
     
     
       9. The method of  claim 1 , wherein the estimated magnetic field map data for at least one magnetic field type describes multiple magnetic field maps for in each case a state that the examination object is in at a different alternative location in each case. 
     
     
       10. The method of  claim 1 , wherein at least one of the alternative locations is describable by a rotation by at least 1°, 2°, or 4°, a translation by at least 1 mm, 2 mm, or 4 mm, or a combination thereof. 
     
     
       11. The method of  claim 1 , wherein determining the control data comprises optimizing to the effect that the MR excitation is optimized for a location range that comprises the alternative locations, the initial location, or the alternative locations and the initial locations. 
     
     
       12. A method for provision of a trained function for determining estimated magnetic field map data, control data, or the estimated magnetic field map data and the control data, the method comprising:
 receiving training input data, wherein the training input data comprises training input magnetic field map data, wherein the training input magnetic field map data for at least one magnetic field type in each case describes a magnetic field map for a state that an examination object is in at an initial location in the MR apparatus; 
 receiving training output data, wherein the training output data comprises training estimated magnetic field map data, training control data, or the training estimated magnetic field map data and the training control data for controlling an MR excitation of the examination object, wherein the training estimated magnetic field map data for at least one magnetic field type in each case describes at least one magnetic field map for in each case a state that the examination object is in at an alternative location that is different compared to the initial location; 
 training the trained function based on the training input data and the training output data; and 
 providing the trained function. 
 
     
     
       13. The method of  claim 12 , wherein the training input data, the training output data, or the training input data and the training output data are generated by scanning, simulation, or scanning and simulation of magnetic field maps. 
     
     
       14. A magnetic resonance (MR) apparatus comprising:
 a processor configured to determine control data for a magnetic resonance (MR) excitation of an examination object using the MR apparatus, the method determination of the control data comprising:
 receipt of input magnetic field map data, wherein the input magnetic field map data for at least one magnetic field type in each case describes a magnetic field map for a state that the examination object is in at an initial location in the MR apparatus; 
 determination of estimated magnetic field map data, wherein the estimated magnetic field map data for at least one magnetic field type in each case describes at least one magnetic field map for in each case a state that the examination object is in at an alternative location that is different compared to the initial location; and 
 determination of control data using the estimated magnetic field map data or using the input magnetic field map data and the estimated magnetic field map data, 
 
 wherein the control data is suitable for the MR excitation of the examination object, and 
 wherein the determination of the estimated magnetic field map data, the determination of the control data, or the determination of the estimated magnetic field map data and the determination of the control data take place based on an application of a trained function, an interpolation function, or the trained function and the interpolation function to the input magnetic field map data. 
 
     
     
       15. In a non-transitory computer-readable storage medium that stores instructions executable by one or more processors to determine control data for a magnetic resonance (MR) excitation of an examination object using an MR apparatus, the instructions comprising:
 receiving input magnetic field map data, wherein the input magnetic field map data for at least one magnetic field type in each case describes a magnetic field map for a state that the examination object is in at an initial location in the MR apparatus; 
 determining estimated magnetic field map data, wherein the estimated magnetic field map data for at least one magnetic field type in each case describes at least one magnetic field map for in each case a state that the examination object is in at an alternative location that is different compared to the initial location; and 
 determining control data using the estimated magnetic field map data or using the input magnetic field map data and the estimated magnetic field map data, 
 wherein the control data is suitable for the MR excitation of the examination object, and 
 wherein the determining of the estimated magnetic field map data, the determining of the control data, or the determining of the estimated magnetic field map data and the determining of the control data take place based on an application of a trained function, an interpolation function, or the trained function and the interpolation function to the input magnetic field map data. 
 
     
     
       16. The non-transitory computer-readable storage medium of  claim 15 , wherein the MR excitation comprises generation of at least one radio frequency (RF) transmit pulse by a transmit coil arrangement of the MR apparatus, generation of at least one gradient pulse by a gradient coil unit of the MR apparatus, or generation of the at least one radio frequency (RF) transmit pulse by the transmit coil arrangement of the MR apparatus and generation of the at least one gradient pulse by the gradient coil unit of the MR apparatus. 
     
     
       17. The non-transitory computer-readable storage medium of  claim 15 , wherein the at least one magnetic field type comprises a B1 field, a B0 field, or the B1 field and the B0 field. 
     
     
       18. The non-transitory computer-readable storage medium of  claim 15 , wherein the estimated magnetic field map data for at least one magnetic field type describes multiple magnetic field maps for in each case a state that the examination object is in at a different alternative location in each case. 
     
     
       19. The non-transitory computer-readable storage medium of  claim 15 , wherein at least one of the alternative locations is describable by a rotation by at least 1°, 2°, or 4°, a translation by at least 1 mm, 2 mm, or 4 mm, or a combination thereof.